1. Field of the Invention
The present invention relates to a method of recording information on a photographic film in which an image to be photographed may be optically recorded on an emulsion surface which is applied to a base of the photographic film.
2. Description of the Related Art
Conventionally, there has been proposed a method in which a transparent magnetic material is applied on a photographic film, and in particular, a negative or positive film, to magnetically record information relating to the negative film and information relating to an image recorded on the negative film (see, for example, International Publication No. WO 90/04205). According to this method, the information can be stored on a magnetic track formed of the transparent magnetic material and corresponding to each image frame. Information to be recorded for each image frame includes: frame number, sensitivity, photographing date, indication of pseudo-zooming/panorama photographing, counterlight/underexposure or overexposure, indication of use of a stroboscope, color temperature, shutter speed, aperture, distance of object(s) photographed, orientation of camera during photographing, place photographed, name of object(s) photographed and other memos relating to the shot.
If such information can be obtained for each photographic frame, the user can readily put the photos in order, store them, retrieve them, or the like. In addition, when a color print is to be obtained from the film photographed by the negative film, since information such as the indication of the pseudo-zooming/panorama, photographing in the counter-light/underexposure or overexposure, use of the stroboscope, the color temperature, or the like are available, it is possible to obtain prints intended during photographing.
In addition, in a film processing laboratory, it is possible to record the amount of exposures for three colors and the like set for the printing for each image frame when the image is printed on photographic paper. At the time of reordering additional prints, this recorded information, such as amount of exposures for three colors and the like, is read, so as to allow the additional prints to be consistent in quality with the original prints.
Incidentally, unlike conventional magnetic tapes, the negative film is intermittently fed frame by frame. However, recording of the information should be conducted when the negative film is being conveyed at a constant speed. In order to relax this constant speed limitation a method called the "three-part code" is proposed in the above-described International Publication No. WO 90/04205.
The three-part code has a timing pulse at the start and end of bit cells in order to represent "0" and "1" of a digital binary signal, the bit cell is divided into two parts to record 0 at the front half and 1 at the latter half or vice versa. If this code is used, then even if the film feeding speed fluctuates somewhat, there is less possibility to make an error in reading "0" and "1".
Further, when the information is actually recorded, the information is coded in terms of "0" and "1" and recorded. digitally. Together with the information a start signal indicating the start of the information, an end signal indicating the end of the information, and at least one of an error detection signal and an error correction signal for preventing errors in digital recording are recorded.
In the above-described Publication, in the simplest error detection signal, a parity check bit is added to yield an even number when a series of data bits are summed rip. For a more sophisticated example of coding method of detecting and correcting errors, a detailed description can be found in items 3. 2. 13. CRC and 3. 2. 14. ECC of ISO/IEC DF 10089-2, concerning a rewritable disk. Such a parity check bit, error detecting code or error correcting code are integral parts of the information recorded and without these data information cannot be reliably read. In general, the recording area for this error detection signal and/or error correction signal comes immediately after the end signal, that is, immediately after a series of information signals.
The start and the end of the information for each image frame can be recognized according to the start signal indicating the start of information, the end signal indicating the end of information, and the error detection signal and/or error correction signal which are essential to write and read correctly with their error preventing capability. These signals make up the total information and make the information writing/reading reliable.
However, if the increase in the conveying speed of the negative film within the camera is too slow, then the negative film may be late in reaching a predetermined speed, and the recording area can become deficient. On the contrary, the negative film may be conveyed faster than the predetermined speed, so that the conveying of a single image frame is finished before the information to be recorded has been recorded. In such a case, the end signal and the error detection signal and/or error correction signal are not recorded, and because these signals are integral parts of the total information, information regarding the image frame can be lost.